Learning theory provides the basis for behavioral interventions. The USMLE behavioral science section always contains questions relating to learning theory.
Learning theory does not apply to behaviors (such as reflexes) which result from maturation of the CNS. In the language of learning theory, behaviors are described as responses. Behaviors include everything that might be seen as an output of the human organism, including breathing, heart beat, hitting a golf ball etc. Environments are described in terms of stimuli. Stimuli include everything from a stressful event to a mother s touch.
Three types of learning are described in this lecture along with the application of each type of learning to behavioral interventions.
Classical conditioning is the brain child of Pavlov: a physiologist interested in the salivating behavior of dogs.
Pavlov discovered that dogs salivate in anticipation of food (when they see it). By accident he discovered that when a bell is rung at the same time that food is presented, eventually the dog will salivate to the sound of the bell.
The dog will salivate when presented with food, with no training. Therefore food is an unconditioned (untrained) response (UCS). The salivation in response to the food occurs without training therefore is a unconditioned response (UCR). The pairing of the bell with the food makes the bell produce the salivation, even when presented without the food. The bell is a conditioned stimulus (CS) and now the salivation becomes a conditioned response (CR)
Pavlov then discovered that other stimuli, similar to the CS could evoke the salivation. For example, another bell sounding slightly different could produce the salivation although not necessarily as strong a response as with the original bell.
When Pavlov continued to ring the bell but no longer presented the food, the response (salivation) would gradually disappear. This decreased response process was called extinction. The process whereby the organism develops a physiological non-response to is called habituation.
Once the dog no longer responds to the bell, Pavlov found that after giving the dog a rest from the process, the dog would again respond to the sound of the bell. However, if no food is paired with the bell, the process of extinction the second time occurs much faster.
So if the dog is conditioned to respond to bell #1, the dog will also respond to bell #2 (generalization). However, if bell #2 is never paired with food, the dog learns to not respond to Bell #2. This process whereby the organism learns which stimulus is associated with food is referred to as discrimination.
Neuroscientists love to study Aplysia (sea slugs) because they have only a few thousand neurons associated with sensation and motor activity. Classical conditioning is used to discover how the Aplysia is conditioned and how the neurons are changed by the conditioning experience. Eric Kandel won the 2000 Nobel Prize in Medicine for his research on the Aplysia, and for describing how neurons respond in learning situations.
When the siphon of the Aplysia is touched, the gill will contract. However, continued touching produces less and less response (habituation). Pairing a touch with a small electric charge restores a large response of the gill. One such pairing (with a very potent, aversive stimulus) and habituation to touch will not occur for at least an hour. The response of the organism to an aversive stimulus is called sensitization. Such research has allowed scientists to identify the neurochemical aspects of habituation and sensitization
Watson wanted to see if classical conditioning applied to humans. He presented little Albert with a white rat. He then frightened the child. The UCS was a scary mask. The CS was the white furry animal. The UCR was fear. The CR was fear. What Watson proved was that children can develop a phobia for objects or people simply as a result of a bad experience.
The little Albert experiment proved how easily one learns to associate an emotional response to certain sights and sounds.
The probability of a behavior re-occurring is directly related to the response that behavior elicits from the environment. If we receive a gold star for taking out the garbage we are more likely to take out the garbage. If we receive criticism for the manner in which we carry out the garbage then we will be much less inclined to take out the garbage next time.
Rewards refer to responses that increase the probability of a behavior re-occurring. The process of rewarding behavior is called positive reinforcement. Positive reinforcement involves the giving of a reward to increase the likelihood that the behavior will re-occur.
Negative reinforcement refers to removal of an unpleasant stimulus (a mother s nagging voice) in order to increase the probability of a behavior re-occurring.
Punishments refer to responses which decrease the likelihood of the behavior reoccurring. Positive punishment is an action (such as spanking) that decreases the chances of a behavior re-occurring. Negative punishment involves the removal of a reward (you re grounded) in order to decrease the likelihood of a behavior reoccurring. Aversive conditioning is a subset of punishment whereby painful or noxious stimuli are used to deal with unwanted behavior.
If a behavior is rewarded on every occurrence, then the behavior will increase in frequency rapidly. However, when one stops rewarding the behavior then the frequency drops off (is extinguished) fairly rapidly.
If a behavior is rewarded on a random basis (called a variable schedule of reinforcement) then the behavior is harder to extinguish. In every day life most of us use a variable schedule with our kids and that turns out to be good for long term learning.
In attempting to teach a complex behavior we may have to positively reinforce (reward) a behavior that is a step toward the behavior wanted. If we want a child to get A s in his courses, we may start by rewarding the child for doing his homework. The idea of rewarding behavior that is a step toward the final desired behavior is called shaping.
Operant conditioning and classical conditioning utilize implicit memory. Operant conditioning involves the development of consistent, over-learned behaviors (habits) as a result of frequent and consistent reinforcement. Verbal memory is not required and in fact, does not play much of a role in the conditioning process.
Reminder: Procedural learning refers to a process of learning (skills, behaviors) without necessarily being conscious of what is being learned. Procedural learning does not require verbal memory. In other words, an individual can learn a task without being able to explain how or why.
Behavior learned in one environment may not transfer to other environments. The youngster who kept his room neat at home may become a slob when he moves into a dorm room
Modeling refers to the process of acquiring behavior patterns by observing others and copying their behaviors. This is especially important for children who adopt many patterns of behavior from their parents. Experiments have shown that kids, in fact, learn a great deal through the process of modeling.
Reminder: The brain s reward system must be functional in order to benefit from operant conditioning. The reward system is dopaminergic. Addictions affect dopamine levels and the same reward system is responsible for creating addictive behavior.
Cocaine directly affects dopamine levels. Once addicted, an individual will rely more heavily on the substance than normal sources of reward (such as affection from others).
When we are faced with behavior that is unwanted (that is, is undesirable for the individual and those around the individual) then behavioral interventions are the most likely type of treatment to apply. Medications can sometimes assist with aberrant behavior, particularly behaviors associated with impulse control. However, medications do not teach new behaviors.
The classic example of the use of classical conditioning for treatment is the use antabuse (Disulfiram) for the treatment of alcohol abuse. Disulfiram produces sensitivity to alcohol which results in a highly unpleasant reaction when the patient under treatment ingests even small amounts of alcohol. Systematic desensitization is used to treat phobias. 1. Teach relaxation using biofeedback. 2. Determine stages of anxiety provoking stimuli. 3. Pair anxiety provoking stimuli with relaxation.
Operant approaches to behavior change. Learn this chart What works is to Reward wanted behavior (Positive Reinforcement) and ignore unwanted behavior (Negative Punishment).
Treatment of obesity involves (1) measurement (a log of food intake, antecedents to food cravings, activities). (2) establish a set of goals (increase activity and decrease food intake), (3) educate on diet, (4) establish a reward structure for certain behaviors, such as refusing food, not having a second plateful at dinner, not snacking etc.; and for increased activity (as opposed to watching TV); (4) re-measure progress on behavior change as well as weight loss. Smoking: List reasons to quit Start exercise program Set target date to quit Know withdrawal symptoms Know triggers (antecedents) Involve others (let them know) Switch brand/cut down/smoke only half Make it inconvenient Find a replacement (juice, pen) Don t empty ashtray One day at a time
Buy yourself a gift with money you save Support Groups Nicotine replacement Anti-depressant (Zyban)